On Jul 15, 2013, at 9:27 PM 7/15/13, Alexander Aring <alex.ar...@gmail.com>
wrote:
> This patch drop the pre and postcount calculation from the
> lowpan_uncompress_addr function.
>
> We use instead a switch case over address_mode value, it's easier
> to understand what's going on there.
Looks OK - visual review only. I find this new code much clearer to understand
and confirm as correct.
- Ralph
>
> Signed-off-by: Alexander Aring <alex.ar...@gmail.com>
> ---
> net/ieee802154/6lowpan.c | 123 ++++++++++++++++++++++-------------------------
> net/ieee802154/6lowpan.h | 8 +--
> 2 files changed, 62 insertions(+), 69 deletions(-)
>
> diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
> index f46c2fb..51fb55c 100644
> --- a/net/ieee802154/6lowpan.c
> +++ b/net/ieee802154/6lowpan.c
> @@ -67,30 +67,6 @@ static const u8 lowpan_ttl_values[] = {0, 1, 64, 255};
>
> static LIST_HEAD(lowpan_devices);
>
> -/*
> - * Uncompression of linklocal:
> - * 0 -> 16 bytes from packet
> - * 1 -> 2 bytes from prefix - bunch of zeroes and 8 from packet
> - * 2 -> 2 bytes from prefix - zeroes + 2 from packet
> - * 3 -> 2 bytes from prefix - infer 8 bytes from lladdr
> - *
> - * NOTE: => the uncompress function does change 0xf to 0x10
> - * NOTE: 0x00 => no-autoconfig => unspecified
> - */
> -static const u8 lowpan_unc_llconf[] = {0x0f, 0x28, 0x22, 0x20};
> -
> -/*
> - * Uncompression of ctx-based:
> - * 0 -> 0 bits from packet [unspecified / reserved]
> - * 1 -> 8 bytes from prefix - bunch of zeroes and 8 from packet
> - * 2 -> 8 bytes from prefix - zeroes + 2 from packet
> - * 3 -> 8 bytes from prefix - infer 8 bytes from lladdr
> - */
> -static const u8 lowpan_unc_ctxconf[] = {0x00, 0x88, 0x82, 0x80};
> -
> -/* Link local prefix */
> -static const u8 lowpan_llprefix[] = {0xfe, 0x80};
> -
> /* private device info */
> struct lowpan_dev_info {
> struct net_device *real_dev; /* real WPAN device ptr */
> @@ -182,50 +158,67 @@ lowpan_compress_addr_64(u8 **hc06_ptr, u8 shift, const
> struct in6_addr *ipaddr,
> return rol8(val, shift);
> }
>
> -static void
> -lowpan_uip_ds6_set_addr_iid(struct in6_addr *ipaddr, unsigned char *lladdr)
> -{
> - memcpy(&ipaddr->s6_addr[8], lladdr, IEEE802154_ADDR_LEN);
> - /* second bit-flip (Universe/Local) is done according RFC2464 */
> - ipaddr->s6_addr[8] ^= 0x02;
> -}
> -
> /*
> - * Uncompress addresses based on a prefix and a postfix with zeroes in
> - * between. If the postfix is zero in length it will use the link address
> - * to configure the IP address (autoconf style).
> - * pref_post_count takes a byte where the first nibble specify prefix count
> - * and the second postfix count (NOTE: 15/0xf => 16 bytes copy).
> + * Uncompress address function for source and
> + * destination address(non-multicast).
> + *
> + * address_mode is sam value or dam value.
> */
> static int
> -lowpan_uncompress_addr(struct sk_buff *skb, struct in6_addr *ipaddr,
> - u8 const *prefix, u8 pref_post_count, unsigned char *lladdr)
> +lowpan_uncompress_addr(struct sk_buff *skb,
> + struct in6_addr *ipaddr,
> + const u8 address_mode,
> + const u8 *lladdr)
> {
> - u8 prefcount = pref_post_count >> 4;
> - u8 postcount = pref_post_count & 0x0f;
> -
> - /* full nibble 15 => 16 */
> - prefcount = (prefcount == 15 ? 16 : prefcount);
> - postcount = (postcount == 15 ? 16 : postcount);
> -
> - if (lladdr)
> - lowpan_raw_dump_inline(__func__, "linklocal address",
> - lladdr, IEEE802154_ADDR_LEN);
> - if (prefcount > 0)
> - memcpy(ipaddr, prefix, prefcount);
> -
> - if (postcount > 0) {
> - memcpy(&ipaddr->s6_addr[16 - postcount], skb->data, postcount);
> - skb_pull(skb, postcount);
> - } else if (prefcount > 0) {
> - if (lladdr == NULL)
> - return -EINVAL;
> -
> - /* no IID based configuration if no prefix and no data */
> - lowpan_uip_ds6_set_addr_iid(ipaddr, lladdr);
> + switch (address_mode) {
> + case LOWPAN_IPHC_ADDR_00:
> + /*
> + * for global link addresses
> + */
> + memcpy(ipaddr->s6_addr, skb->data, 16);
> + skb_pull(skb, 16);
> + break;
> + case LOWPAN_IPHC_ADDR_01:
> + /*
> + * fe:80::XXXX:XXXX:XXXX:XXXX
> + */
> + memset(&ipaddr->s6_addr[0], 0xFE, 1);
> + memset(&ipaddr->s6_addr[1], 0x80, 1);
> + memcpy(&ipaddr->s6_addr[8], skb->data, 8);
> + skb_pull(skb, 8);
> + break;
> + case LOWPAN_IPHC_ADDR_02:
> + /*
> + * fe:80::ff:fe00:XXXX
> + */
> + memset(&ipaddr->s6_addr[0], 0xFE, 1);
> + memset(&ipaddr->s6_addr[1], 0x80, 1);
> + memset(&ipaddr->s6_addr[11], 0xFF, 1);
> + memset(&ipaddr->s6_addr[12], 0xFE, 1);
> + memcpy(&ipaddr->s6_addr[14], skb->data, 2);
> + skb_pull(skb, 2);
> + break;
> + case LOWPAN_IPHC_ADDR_03:
> + /*
> + * fe:80::XXXX:XXXX:XXXX:XXXX
> + * \_________________/
> + * lladdr
> + */
> + memset(&ipaddr->s6_addr[0], 0xFE, 1);
> + memset(&ipaddr->s6_addr[1], 0x80, 1);
> + memcpy(&ipaddr->s6_addr[8], lladdr, IEEE802154_ADDR_LEN);
> + /*
> + * second bit-flip (Universe/Local)
> + * is done according RFC2464
> + */
> + ipaddr->s6_addr[8] ^= 0x02;
> + break;
> + default:
> + pr_debug("Invalid address mode value: 0x%x\n", address_mode);
> + return -EINVAL;
> }
>
> - pr_debug("uncompressing %d + %d => ", prefcount, postcount);
> + pr_debug("Reconstructed ipv6 addr is:\n");
> lowpan_raw_dump_inline(NULL, NULL, ipaddr->s6_addr, 16);
>
> return 0;
> @@ -967,8 +960,7 @@ lowpan_process_data(struct sk_buff *skb)
>
> /* Source address uncompression */
> pr_debug("source address stateless compression\n");
> - err = lowpan_uncompress_addr(skb, &hdr.saddr, lowpan_llprefix,
> - lowpan_unc_llconf[tmp], _saddr);
> + err = lowpan_uncompress_addr(skb, &hdr.saddr, tmp, _saddr);
> if (err)
> goto drop;
>
> @@ -988,8 +980,7 @@ lowpan_process_data(struct sk_buff *skb)
> }
> } else {
> pr_debug("dest: stateless compression\n");
> - err = lowpan_uncompress_addr(skb, &hdr.daddr, lowpan_llprefix,
> - lowpan_unc_llconf[tmp], _daddr);
> + err = lowpan_uncompress_addr(skb, &hdr.daddr, tmp, _daddr);
> if (err)
> goto drop;
> }
> diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
> index 4b8f917..3b64644 100644
> --- a/net/ieee802154/6lowpan.h
> +++ b/net/ieee802154/6lowpan.h
> @@ -193,10 +193,12 @@
> /* Values of fields within the IPHC encoding second byte */
> #define LOWPAN_IPHC_CID 0x80
>
> +#define LOWPAN_IPHC_ADDR_00 0x00
> +#define LOWPAN_IPHC_ADDR_01 0x01
> +#define LOWPAN_IPHC_ADDR_02 0x02
> +#define LOWPAN_IPHC_ADDR_03 0x03
> +
> #define LOWPAN_IPHC_SAC 0x40
> -#define LOWPAN_IPHC_SAM_00 0x00
> -#define LOWPAN_IPHC_SAM_01 0x10
> -#define LOWPAN_IPHC_SAM_10 0x20
> #define LOWPAN_IPHC_SAM 0x30
>
> #define LOWPAN_IPHC_SAM_BIT 4
> --
> 1.8.3.2
>
>
> ------------------------------------------------------------------------------
> See everything from the browser to the database with AppDynamics
> Get end-to-end visibility with application monitoring from AppDynamics
> Isolate bottlenecks and diagnose root cause in seconds.
> Start your free trial of AppDynamics Pro today!
> http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk
> _______________________________________________
> Linux-zigbee-devel mailing list
> Linux-zigbee-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
------------------------------------------------------------------------------
See everything from the browser to the database with AppDynamics
Get end-to-end visibility with application monitoring from AppDynamics
Isolate bottlenecks and diagnose root cause in seconds.
Start your free trial of AppDynamics Pro today!
http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk
_______________________________________________
Linux-zigbee-devel mailing list
Linux-zigbee-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
